Problem: Solve for $k$ : $3 + k = 25$
Answer: Subtract $3$ from both sides: $ \begin{eqnarray} \\ 3 + k &=& 25 \\ \\ {-3} && {-3} \end{eqnarray} $ $ \begin{eqnarray} \hphantom{3 + k} &\hphantom{=}& \hphantom{25} \\ k &=& 25 {- 3} \\ \end{eqnarray} $ Simplify. $ k = 22$